Outlines of astronomy / By Sir John F.W. Herschel.

  • John Frederick William Herschel
Date:
1849
Catalogue details

Licence: Public Domain Mark

Credit: Outlines of astronomy / By Sir John F.W. Herschel. Source: Wellcome Collection.

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    CHAPTER IV. OF GEOGRAPHY. equilibrium modified by centrifugal force. Variation of gravity on its surface. Statical and dynamical measures of gravity. The pendulum. Gravity to a spheroid. Other effects of the Earth’s rotation. Trade winds. Determination of geographical positions — of latitudes — of longitudes. Conduct of a trigonometrical survey. Of maps. Projec- tions of the sphere. Measurement of heights by the barometer Page 125 CHAPTER V. OF URANOGRAPHY. sion and declination. Celestial objects distinguished into fixed and erratic. Of the constellations. Natural regions in the heavens. The Milky Way. The Zodiac. Of the ecliptic. Celestial latitudes and longitudes. Precession of the equinoxes. Nutation. Aberration, Refraction. Parallax. Summary view of the uranographical cor- rections - - - - r - - - 176 CHAPTER VI. OF THE SUN’S MOTION. variable. Variation of its distance concluded. Its apparent orbit an ellipse about the focus. Law of the angular velocity. Equable description of areas. Parallax of the Sun. Its distance and magnitude. Copernican explanation of the Sun’s apparent motion. Parallelism of the Earth’s axis. The seasons. Heat received from the Sun ia different parts of the orbit. Mean and true longitudes of the Sun. Equation of the centre. Sidereal, tropical, and anomalistic years. Physical constitution of the Sun. Its spots. Facule. Probable na- ture and cause of the spots. Atmosphere of the Sun. Its supposed clouds. Temperature at its surface. Its expenditure of heat. Ter- restrial effects of solar radation - - - - - 205 CHAPTER VIi. distance, and real diameter. First approximation to its orbit. An ellipse about the Earth in the focus. Its excentricity and inclination. Motion of its nodes and apsides. Of occultations and solar eclipses generally. Limits within which they are possible. They prove the Moon to be an opaque solid. Its light derived from the Sun. Its phases. Synodic revolution or lunar month. Of eclipses more par-